My mri showed subtle enhancement in the right cerebellum concerning for metastatic disease.how worried should i be?

If the MRI interpretation by the radiologist reads as you have indicated, I would definitely follow up with the doctor who ordered the test to get a better idea of what your next steps should be. These results appear to be very significant and need to be clarified.

The findings are not specific, and could represent vascular event, local inflammation, or even a secondary immune effect from a distal cancer. If this were a metastasis, it would be more commonly noted in a different location. The most common causes for a met. include lung, breast, skin, G.I., kidney. If you do have primary source, this needs focused attention NOW.